Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1998-10-30
2001-10-09
Karlsen, Ernest (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S765010, C439S071000
Reexamination Certificate
active
06300781
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of semiconductor device handling, and more specifically to sockets for the insertion of surface mounted, high pin count semiconductor packages, and more particularly to test and burn in sockets for Ball Grid Array (BGA) integrated circuit packages.
DESCRIPTION OF THE PRIOR ART
Surface mounted, high pin count integrated circuit packages have been dominated by Quad Flat Packs (QFP's) with various pin configurations. These packages have closely spaced leads for making electrical connections distributed along the four edges of the flat package. These packages have become limited by being confined to the edges of the flat package even though the pin to pin spacing is small. To address this limitation, a new package, a Ball Grid Array (BGA) is not so confined because the electrical contact points are distributed over the entire bottom surface of the package. More contact points can thus be located with greater spacing between the contact points than with the QFP's. These contacts are solder balls that facilitate flow soldering of the package onto a printed circuit board. BGA's are therefore popular alternatives the QFP's.
Sockets that accept BGA's are required for device testing, burn-in, re-programming and at times for production use where the integrated circuit must be replaced. Currently, in order to test a BGA device, the contactor elements of the BGA device are inserted into a contactor plate having a plurality of sockets. The contactor plate is coupled to a Device Under Test (DUT) board, which is coupled to a tester. In order to test the BGA device, the tester sends electrical signals to and receives electrical signals from the BGA device via the electrical paths provided by the contactor plate and the DUT board.
While current contactor plates do work, there exist several problems with the contactor plates.
First, many current contactor plates consist of a plurality of sockets for receiving the contactor elements of the BGA device.
Second, certain contactor plates can only be used for certain types of testing equipment. As such, different contactor plates are required for different types of testing equipment.
Third, contactor plates only accommodate BGA devices having a particular array type or a particular ball pitch. This requires that there is a different contactor plate for different size BGA packages.
Therefore, the need exists to provide a contactor plate that provides reliable electrical contacts for testing BGA devices. The contactor plate must be capable of being used on different types of testing and handling equipment. The contactor plate must also be adaptable to allow the contactor plate to handle a variety of different size BGA devices.
U.S. Pat No. 5,688,127 (Staab et al.) shows a universal contactor system of testing multiple size BGA devices on multiple types of test equipment. However, this patent does not show the exact details of the present invention.
U.S. Pat. No. 5,646,447 (Ramsey) shows a test socket for BGA. However, this reference differs from the present invention.
U.S. Pat. No. 5,578,870 (Farnsworth et al.) shows another top loading test socket for BGA's.
U.S. Pat. No. 5,127,837 (Shah et al.) discloses an electrical connector and Integrated circuit tester with a wadded wire plunger.
SUMMARY OF THE INVENTION
In accordance with the present invention, it is an objective of the present invention to provide an improved contactor system and method for testing BGA devices.
Another objective of the present invention is to provide an improved contactor system and method that can be used to test BGA devices of various sizes.
Another objective of the present invention is to provide an improved contactor system and method that can be used for testing BGA devices on multiple types of testing equipment.
Another objective of the present invention is to provide an improved contactor system and method that provides a reliable electrical connection for testing BGA devices.
In accordance with the objectives of the present invention a BGA interface socket is designed that accommodates various size BGA packages.
The number of contact points and the pitch between the contact points of a specific BGA device is a given and is fixed. Also fixed is the array of pads or contact points on the surface of the loadboard of the BGA device tester. The present invention provides the means of quickly and reliably establishing electrical connections between these two interfaces. The interface socket of the present invention eliminates the need to use relatively expensive sockets for different sizes of BGA devices. In the present environment a socket is unique for a given BGA device size and BGA ball pitch. The interface socket of the present invention serves as an interface between the BGA semiconductor device that is being tested and the tester.
REFERENCES:
patent: 5127837 (1992-07-01), Shah et al.
patent: 5537051 (1996-07-01), Jalloul et al.
patent: 5578870 (1996-11-01), Farnsworth et al.
patent: 5646447 (1997-07-01), Ramsey et al.
patent: 5688127 (1997-11-01), Staab et al.
patent: 5810607 (1998-09-01), Shih et al.
patent: 6046597 (2000-04-01), Barabi
patent: 6062873 (2000-05-01), Kato
Tan Chee-Keong
Tan Wee Boon
Yap Liop Jin
Ackerman Stephen B.
Karlsen Ernest
Kobert Russell M.
Saile George O.
ST Assembly Test Services PTE LTD
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